The major objective of the proposed research is to study translation of messenger RNA in the mouse oocyte and ovum. This will be done by micro-injecting an exogenous messenger RNA (rabbit globin message) into the egg cell and studying the translation of known amounts of this message at the different stages. The specific aims are: (1) Determine whether the translation capacity of the egg cell is different in growing oocytes, mature oocytes, unfertilized ova and fertilized ova. (2) Determine whether the translation efficiency of an infected message is different in growing oocytes, mature oocytes, unfertilized ova and fertilized ova. The stages to be examined bracket key biological transitions and the processes to be studied are fundamental in every cell. Similar studies have not been previously reported, because of the limited amount of tissue available and difficulty of the techniques. However the results will contribute substantially to ouyr understanding of the biology of these cells.